Originally posted by Archie:I've seen the Alum Radiators on EBay (there's one on EBay right now http://cgi.ebay.com/ebaymot...IT&item=200276227512 I've been tempted to buy one to test myself. That EBay ad states that it's rated at 850 hp, I don't get how a radiator can be rated via hp. That statement is one of the main reasons I haven't bought one yet for testing.
Archie
I'm a member of the Society of Automotive Engineers student chapter at Texas A&M University and I've heard an instructor who teaches automotive classes explain the hp rating. An engine's power is split roughly into three different outputs: one is at the flywheel, one goes out the exhaust, and one is radiated as heat.
By this logic, a motor that makes 300hp at the flywheel actually makes 900hp total. It also says that if you have a motor with 300hp at the flywheel, you have to radiate 300hp of heat. This sounds odd, so lets talk about this in metric. 1hp = 746 Watts. This means that the radiator would have to be capable of dissipating 223.8 Kilowatts of heat. A Watt being a rating of Joules per second. This means that this is a rating with respect to time. That's 223.8 KiloJoules per second.
From wiki, I found these unit conversions:
quote
1 joule is exactly 107 ergs.
1 joule is approximately equal to:
* 6.2415 ×1018 eV (electronvolts) * 0.2390 cal (calorie) (small calories, lower case c) * 2.3901 ×10−4 kilocalorie, Calories (food energy, upper case C) * 9.4782 ×10−4 BTU (British thermal unit) * 0.7376 ft·lbf (foot-pound force) * 23.7 ft·pdl (foot poundals) * 2.7778 ×10−7 kilowatt hour * 2.7778 ×10−4 watt hour * 9.8692 ×10−3 litre-atmosphere
It is true that the radiator will cool differently based on your configuration. Fan flow rate, availability of cool air, etc. Also, how you run the engine. Your engine won't run at 300hp all the time. It may idle at 100hp.
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10:41 AM
KEV Member
Posts: 2590 From: Green Isle, MN Registered: Dec 2000
He states that it is much better regarding its capacity than the first radiator they offered that is still available for $155 which has a single 1" wide row spaced a 1/2" apart. The newer heavy duty model is made from stock radiators, has a 2" core and 11/16" rows spaced 3/8" apart. The core area is 19" x 14" and the listing states it is a 3 row radiator. I understand that 11/16" stacked on top of itself 3 deep is a little more than 2" wide but I'll assume it was rounded or ask for clarification when I get ready to buy one.
He also states that a little fitting will be required because the tanks are 1/4" wider and may not fit in the mounts perfectly but it is a tested fit otherwise.
I have one ordered and it will be here next tuesday. I'll post pictures of it after it arrives.
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1999 GMC Jimmy 2dr 4x4 1996 Chevy Lumina LS 1986 Fiero Base Coupe...NO OPTIONS !! 1985 Fiero GT 3800 N/A-sometime this year 3800S/C..maybe 1984 Fiero Indy-Restoring back to former glory
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01:34 PM
Dec 7th, 2008
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
Originally posted by Rolling Thunder: An engine's power is split roughly into three different outputs: one is at the flywheel, one goes out the exhaust, and one is radiated as heat.
By this logic, a motor that makes 300hp at the flywheel actually makes 900hp total. It also says that if you have a motor with 300hp at the flywheel, you have to radiate 300hp of heat.
This is almost correct.
By this logic only about a third of the heat energy of gasoline end up at the flywheel.
That is about right, (maybe a little high even) but it's incorrect to say that the engine with 300 hp at the flywheel actually makes 900 hp.
That extra energy is just lost due to the inefficiency of the design of the internal combustion engine. There are ways to capture some of it as in a turbo, but the second law of thermodynamics tells us that it's impossible to capture all of it. So the hp measured at the flywheel is a true indication of how much of the energy of the gasoline is converted to useful work.
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08:11 PM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
Don`t get me wrong, i understand your point, i`m already using a copper/brass rad. in one of my fieros, it was made by a local shop using a 3 core panel and it fit perfect the cost? $174.00 including 1gal. of coolant. But my point is that like conduction, radiation is a unique and independent form of heat transfer. Therefore, radiation is fundamentally different from conduction in that it describes the transfer of heat between two substances which are not in contact with each other. . How much heat an object radiates is determined by it's temperature, the temperature of the surrounding environment and the object's emissivity factor. So, in a car radiator or cooling system it`s fundamental the amount of energy or radiated heat that flows trough the cooling fan to be exchanged with fresher air and help mantein a lower temp. So it`s a matter of preferences and necesitys.
The chart below gives the infrared radiation reflectivity (emissivity) of some common materials:
Material Reflectivity Aluminum Bright 90-95% Anodized 45% Oxidized 70-80% most common in rads. Brass Bright 97% Oxidized 39% Chromium Polished 92% Copper Bright 95% Oxidized 22% most common in rads. Steel Polished 45% Oxidized 15% Nickel Polished 95% Oxidized 5% Zinc Bright 77% Oxidized 77% Paint White 10% Black 14% Rubber 6% Water 8%
Even though it's called a "radiator" a car's cooling system transfers heat by conduction from the coolant to the radiator fins, and from conduction/convection to the atmosphere. Very little heat transfer is via radiation. Copper is a better CONDUCTOR of HEAT than aluminum. The reason to use aluminum is because it's LIGHTER. Aluminum radiators have to be larger to get the same heat transfer, but even larger they still weigh less than a comparable copper/brass radiator.
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11:29 PM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
By this logic only about a third of the heat energy of gasoline end up at the flywheel.
That is about right, (maybe a little high even) but it's incorrect to say that the engine with 300 hp at the flywheel actually makes 900 hp.
That extra energy is just lost due to the inefficiency of the design of the internal combustion engine. There are ways to capture some of it as in a turbo, but the second law of thermodynamics tells us that it's impossible to capture all of it. So the hp measured at the flywheel is a true indication of how much of the energy of the gasoline is converted to useful work.
Exactly. The amount of fuel used might have contained enough energy to create 900HP, but the engine is unable to convert all of that into useful work - the rest is given off as wasted heat, etc.
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11:31 PM
May 21st, 2009
Rolling Thunder Member
Posts: 1244 From: College Station, TX Registered: Aug 2008
E-Bay seller or manufacturer? I called the manufacturer (Champion Cooling) directly and got the last two they had in stock for $155 each about 3 weeks ago. Shipping was discounted also @ $35 if I remember correctly. They did say that was introductory pricing and honored it because I bought more than one so you might not get the same deal but they still might be cheaper than a E-Bay reseller.
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01:22 PM
Rolling Thunder Member
Posts: 1244 From: College Station, TX Registered: Aug 2008
E-Bay seller or manufacturer? I called the manufacturer (Champion Cooling) directly and got the last two they had in stock for $155 each about 3 weeks ago. Shipping was discounted also @ $35 if I remember correctly. They did say that was introductory pricing and honored it because I bought more than one so you might not get the same deal but they still might be cheaper than a E-Bay reseller.
